Dual-Mode Charge Pump Regulator with Active Current Sinking
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Solution Overview
Problem
Conventional high-voltage charge pump circuits, such as Dickson charge pump circuits, face challenges in maintaining a fixed high-voltage output due to the inverse relationship between output voltage and current, requiring excess current to be dumped in diode clamp circuits, which is inefficient and varies with load conditions.
Innovation Solution
A dual-mode voltage generator system with a control circuit that includes a current sink transistor and a dual-output op amp, using a Zener diode configuration for reference voltage and a voltage divider to actively regulate the output voltage, allowing for multiple control options to manage high and low voltage levels, thereby maintaining a constant output voltage by sinking excess current to ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Zener diode clamp circuit is used to regulate the high-voltage output, then the output voltage is held at a fixed value, but excess current is dumped in the diode clamp circuit resulting in energy loss
Solution Approach 1:
The patent employs a feedback mechanism where the output voltage is monitored and compared against a reference voltage, and the difference is used to control a MOSFET switch that regulates the charge pump operation. This active feedback control allows precise voltage regulation while minimizing excess current dissipation by dynamically adjusting the pump operation based on actual load requirements.
Solution Approach 2:
The charge pump circuit is designed to automatically adjust its operation based on the output voltage feedback, eliminating the need for external Zener diode clamp circuits to dissipate excess current. The circuit self-regulates by controlling the pump's switching based on the voltage difference between the output and reference voltages, thereby serving its own regulation needs without wasting energy.
2Stability of the object's composition
If excess current is produced to maintain fixed output voltage, then the output voltage remains stable, but the charge pump circuit operates inefficiently
Solution Approach 1:
The patent transitions from a static voltage regulation approach (Zener diode clamp) to a dynamic regulation approach using a MOSFET switch controlled by feedback. The MOSFET's on-resistance and switching behavior dynamically adjust the charge pump operation to match the actual load requirements, maintaining voltage stability while optimizing energy efficiency by producing only the necessary current rather than excess current.
3Device complexity
If a passive regulation technique using Zener diodes is used, then the circuit structure is simple, but the output voltage varies with load current
Solution Approach 1:
The patent introduces a feedback control loop that monitors the output voltage and adjusts the charge pump operation accordingly. This feedback mechanism compensates for load current variations, maintaining consistent output voltage despite changes in load conditions. The feedback approach adds some circuit complexity but significantly improves voltage consistency compared to passive Zener diode regulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively regulates the output voltage at a fixed level, independent of load current variations, providing efficient operation and power management for non-volatile memory designs with varying density and current requirements.
Implementation Method 1
A reference voltage source provides a fixed reference voltage
Implementation Method 2
A voltage divider circuit provides a feedback signal proportional to the output voltage
Implementation Method 3
A dual-output op amp compares the feedback signal to the reference voltage and provides control signals
Implementation Method 4
The current sink transistor is activated to sink current from the output terminal to ground
Data Source
AI summary
A voltage generator has a control circuit for controlling a dual-mode charge pump that has multiple control options provided by an optional pull down control signal and an optional stop control signal. The dual-mode charge pump is enabled by a high voltage enable control signal from a control circuit to provide a high-voltage output voltage level Vpp or a low-voltage output voltage level Vdd. A current sink transistor is coupled from the output of the dual-mode charge pump to a ground reference through a current sink control switch transistor that is turned on by the optional pull down control signal. A dual output op amp compares a fixed voltage reference to a voltage proportional to the output voltage of the charge pump. The op amp has a high voltage output signal terminal that turns on the current sink transistor and a low voltage output signal that is coupled to the control circuit.